The applicant of the present invention previously developed a wake straightener attached to a helmet and a helmet with the wake straighteners so as to prevent the helmet from being pulled back by wind pressure when a user drives a motorcycle while putting on the helmet, and filed an application of the wake straightener and the helmet (see Patent Document 1). This wake straightener is designed to introduce an airflow going beyond a top of the helmet to be separated at a rear position as far from the helmet as possible, and to suppress generation of negative pressure in rear portions of the helmet. In a side view, the wake straightener has a structure with a flat top portion extending rearward to be continuous tangentially from the top of the helmet (near an uppermost portion thereof in a driving posture).
Patent Document 1: Japanese Utility Model Registration No. 3050720